2MASS J11151597+1937266: A Young, Dusty, Isolated, Planetary-mass Object with a Potential Wide Stellar Companion

• Published in: The Astrophysical journal Vol. 853; no. 1; pp. 75 - 83
• Main Authors: Theissen, Christopher A., Burgasser, Adam J., Gagliuffi, Daniella C. Bardalez, Hardegree-Ullman, Kevin K., Gagné, Jonathan, Schmidt, Sarah J., West, Andrew A.
• Format: Journal Article
• Language: English
• Published: Philadelphia The American Astronomical Society 20-01-2018; IOP Publishing
• Subjects: Astrophysics; brown dwarfs; circumstellar matter; Deposition; Extrasolar planets; Gravitation; H alpha line; Infrared spectra; Infrared spectroscopy; infrared: stars; Luminosity; Near infrared radiation; Near infrared spectroscopy; Planets; proper motions; Sky surveys (astronomy); Spectral energy distribution; Spectrum analysis; stars: individual (2MASS J11151597+1937266, 2MASS J11131089+2110086)
• ISSN: 0004-637X; 1538-4357
• DOI: 10.3847/1538-4357/aaa0cf

We present 2MASS J11151597+1937266, a recently identified low-surface-gravity L dwarf, classified as an L2γ based on Sloan Digital Sky Survey optical spectroscopy. We confirm this spectral type with near-infrared spectroscopy, which provides further evidence that 2MASS J11151597+1937266 is a low-surface-gravity L dwarf. This object also shows significant excess mid-infrared flux, indicative of circumstellar material; and its strong H emission (EWH = 560 82 ) is an indicator of enhanced magnetic activity or weak accretion. Comparison of its spectral energy distribution to model photospheres yields an effective temperature of . We also provide a revised distance estimate of 37 6 pc using a spectral type-luminosity relationship for low-surface-gravity objects. The three-dimensional galactic velocities and positions of 2MASS J11151597+1937266 do not match any known young association or moving group. Assuming a probable age in the range of 5-45 Myr, the model-dependent estimated mass of this object is between 7 and 21 MJup, making it a potentially isolated planetary-mass object. We also identify a candidate co-moving, young stellar companion, 2MASS J11131089+2110086.